Alonzo t



(No Model.)

A. T. BOONE. DOOR KNOB ALARM.

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Patented Jan 9,188'3.

To all whom. t'tmay concern f; UNITED STATEs PATENT OFFICE.

ALONZO r. BOONE, or CHICAGO, IL

LINOIS, ASSIGNOR OF ONE-HALF TO RUFUS H. SANBORNE.

DOOR-KNOB ALARM.

SPECIFICATION forming part of Letters Patent No. 270,199, dated January 9, 18E3.

' Application filed April 20, 1882. (No model.)

Be it knownthat I, ALONZO '1. Room], a

citizen of the United States, residing at the eityof Chicago, in the State of Illinois, have made certain new and useful Improvements in Burglar-Alarms, of which the following is the specification. v

The nature and object of this invention is to construct a burglar-alarm that will be efl'ective in action and that burglars cannot destroy the action of, so as to preventthe alarm when the door is opened, I r V Figure l is an upright view with the casing removed, showing the working of the operative parts of the alarm. Fig. 2 is a side elevation through linew w of Fig. 1. Fig. 3 is a front view with a portion of the casing, showing the indicator'on outside of casing and the operative parts indicated by dotted lines. Fig. 4 is a view of the indicator and cranklever.

Similar letters of reference refer to similar parts in-the dilferent drawings. 4

A A are two levers loosely attached to the bed-piece B by means of the posts D D. To the upper ends of these levers are fastened the hammers E E by means of the wires G G.

F F are coiled springs, fastened at one end to the posts N N and at the other ends to the wires G G. i

H H are pawls loosely attached to thelower ends of the levers A A, and stand facing each other.

1 l are pins on the under side of each pawl, and fastened to the levers A A, to prevent the pawls falling down.

K K are springs, one end of each fastened to theposts D D; thence turning with a coil they pass along the upper surfaces of the pawls H H,and the other ends, aa, cross each other at J, Fig. 1. At the point where they pass along the upper surface of pawls H H they are tastened to each pawl, and the ends a or, beyond the point where they are fastened to the pawls, serve the purpose of levers to lift the'pawls; hence I call these ends lever ends a a.

L is a toothed segment, having three or more teeth, t t, rigid or stationary, as agalnst yielding teeth. This segment works upon the ordinary spindle of the door-lock, and the hole through which the spindle works ispolygonal, so as to allow a square on diamond-shaped shank to pass through it.

O is the hell, on the inside of which the hammers E E strike. Surrounding the bell and at the top of the alarm,exte nding to the bed-plate B, is the hood vW. This hood and the hell are fastened to the same post by means of the screw P. In the hood are the holes R R for the escape of sound. The lower part of the hood'extends downward onlyto the edge of the bell, as shown at S, Fig. 2.

T is a case covering the operative parts of the alarm and extending up under the bellO,

so as to expose the operative parts.

V, Figs. 3 and 4, is an indicator placed upon the outside ofcase T. It is attached to the as shown inFig. 2. In Fig. lit is cut away vented from moving down by the pins II.

This causes the lower arms of the levers A A to-be pushed back, which lifts the hammers E E. The instant the teeth 15 t have passed by the ends of the pawls H the coiled springs F F cause the hammers to strike the hell 0 and give the alarm. When it is-desired to turn the knob or open the door without giving the alarm, the indicator V is turned in a vertical position, with the point extendingdirectly the lever ends a a at J, which lifts the pawls beyond the reach of the teetht if, when the knob Z can be turned and no alarm given.

The hood W, surrounding the bell,prevents a burglar from introducing any instrument above the alarm to deaden the soupd ofthe bell, and the plate B prevents the boring of any hole under the bell for the same purpose. The hood Wand plate B are made of metal. This alarmcan be attached to any ordinary door-lock, and the spring in the door-lock upward, thus causing the crank-lever Y. to lift 1 will return the toothed segment to its vertical I claim IO position, as shown in Figs. 1 and 3. The knob The combination of the indicator V, crank- Z is turned either way to open the door, and lever Y,pawlsH H, and lever ends a a,fixedly at the same time the alarm is given. attached to said pmvls as and for thepurpose I am aware that devices have been used to shown. l allow the spindle of the alarm to be turned ALONZO 'l. BOONE. withoutgiving thealarm; but the meansherein Witnesses: shown to accomplish this purpose are believed J AS. A. GOWLEs, to be new. 7 I A. SHOGREN'. 

